We have determined that linoleic acid hydroperoxide (LAHP) and cumene hydroperoxide in the presence of a heme compound such as hematin or methemoglobin will activate N-hydroxy-2-acetylaminofluorene (N-OH-AAF) into the more potent carcinogen N-acetoxy-2-acetylaminofluorene (N-OAC-AAF) and 2-nitrosofluorene (NOF). We propose to use spin trapping agents to determine if hydroxyl radicals are the primary radicals responsible for the activation of N-OH-AAF via the nitroxyl free radical intermediate. We propose to determine if some antioxidants used in the food industry such as butylated hydroxytoluene (BHT) and butylated hydroxy anisole (BHA) as well as vitamin E will inhibit the N-OH-AAF activation mechanism described above. We propose to determine if epithelial cells of mammary gland of rats have enzymes necessary to activate N-OH-AAF via the peroxidase or free radical route described above. We also propose to use low-temperature electron spin resonance (ESR) techniques to determine the nature of N-OH-AAF interaction with heme compounds and determine why cyanide does not inhibit the activation of N-OH-AAF in the horse radish peroxidase (HRP)-H2O2 system. BIBLIOGRAPHIC REFERENCES: Floyd, R.A.: (1976) Microsome Catalyzed Conversion of N-Hydroxy-N-Acetyl-2-Aminofluorene by Cumen-Hydroperoxide. Life Sci. 18, 189-196. Floyd, R.A., Soong, L.M., and Culver, P.L.: (1976) Horseradish Peroxidase: Hydrogen Peroxide-catalyzed Oxidation of the Carcinogen N-Hydroxy-N-acetyl-2-aminofluorene as Effected by Cyanide and Ascorbate. Cancer Res. 36: 1510-1519.